1. Field of the Invention
The present invention is directed to a method of producing light conducting fibers which method includes providing a base member of an optical material, depositing at least one optical material forming layer on a surface of the base member and then subsequently transforming each of the layers into a film of optical material.
2. Prior Art
Thin glass fibers are utilized as transmission medium in optical communication transmission systems. The glass fibers generally consist of a fiber core and cladding composed of materials which have been selected so that the refractive index of the core is higher than the refractive index of the material forming the cladding.
A cladded light conducting fiber with a stepped index profile and a cladded light conducting fiber with a gradient index profile are known. A stepped index profile means that the refractive index abruptly changes its value at the boundary surface of the core and cladding so that the core has a higher refractive index than the cladding. A gradient index profile means that the light conducting fiber has a higher refractive index in the vicinity of the fiber axis and that this refractive index continuously decreases with an increasing distance from the fiber axis. Both types of fibers can have an additional synthetic material casing which is to protect the fiber particularly from mechanical damages. In each type of light conducting fibers, light can be guided or conveyed over very long distances.
The technique of chemical vapor deposition is known for the production of such fibers, for example see the publication by J. B. Mac Chesney, P. B. O'Connor, F. V. DiMarcello, J. R. Simpson, P. D. Lazey, "Preparation of Low Loss Optical Fibers Using Simultaneous Vapor Phase Deposition and Fusion", 10th International Congress of Glass, (1974), pages 6-40 to 6-45. To form an optical fiber having a stepped index profile, a double crucible method has been suggested (see H. G. Unger, "Optical Communications Technique", 1976, Berlin, pages 39 and 40).